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Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training

Friday, July 28, 2017

New Syntax for Hash Tables with Select-Object

Wow! I am actually
getting around to blogging this year.
This has been an epic year in terms of how busy I have been. Between speaking at both the PowerShell
Conferences in Europe and Asia, but also expanding my client base in Asia and
the Pacific islands, I have been busy.
Oh, let’s not forget adding Windows Server 2016 classes, Security+ and
my work on the Azure platform.

OK, yes I have been busy.
At some point, what I have been learning does get spilled over into my
classes and this blog.

One of the sticky points with learning PowerShell has been
the creation of calculated properties with Select-Object. To do so you need to use a hash table, associative
table, or dictionary. What you call it
depends on your background. Just
remember that most IT pros who take my PowerShell classes are not programmers
and have never been trained as such.
Makes for an interesting week for me.

Below is an example of how we have been teaching calculated properties.

Get-Process |

Select-Object-PropertyName,

@{

Name = 'VirtMemory'

Expression = {$PSItem.VM}

}

You
could short hand it as such.

Get-Process |

Select-Object-PropertyName,
@{N = 'VirtMemory'; E = {$PSItem.VM}}

Well,
that hash table is the problem. I have
not found a way to eliminate it, but I have found a way to write it a different
way.

$Hash1 = @{ 'Name'
= 'VirtMemory'; Expression = {$PSItem.VM}}

Get-Process | Select-Object-PropertyName,
$Hash1

The
idea is to break it up into multiple parts so the student can focus more on
what is going on and less on the confusing syntax used with Select-Object. You
can add additional calculated properties as shown below.

$Hash1 = @{ 'Name'
= 'VirtMemory'; Expression = {$PSItem.VM}}

$Hash2 = @{ 'Name'
= 'WorkMemory'; Expression = {$PSItem.WS}}

Get-Process | Select-Object-PropertyName,
$Hash1, $Hash2

This
technique will not work for all. If what
you are using works for you, then continue to use your technique. I will be introducing this syntax in my
PowerShell class next week in Phoenix to gauge the class response to this
technique as a step in their understanding of how to perform this very common
task and understand it.